Generally, automatic car couplers used on mass and/or rapid transit railway vehicles not only effect the mechanical coupling and uncoupling operations between adjacent cars, but also perform the connecting and disconnecting operations of the electrical contacts of the trainline circuits and various pressure connectors of the pneumatic lines of the train. In practice, a coupler control circuit for a married pair of self-powered transit cars usually permits the uncoupling operation to be initiated at either of the railway cars. In operation, the trainman powers up the transit car that he wishes to pull away and then he initiates the uncoupling sequence by closing an electrical switch. The car on which the uncoupling procedure is activated will be free to move away while the left-behind car will go into an emergency operating mode in which the brakes are set. However, this indiscriminate method of uncoupling is not only unsafe, but also troublesome on certain transit trains, such as, unpowered passenger cars which are pulled by a locomotive. This is true, especially when the uncoupling must be initiated outside the transit cars, such as, the double deck passenger cars which are used on some properties. When the individual, who performs the uncoupling operation between two unpowered trailing cars, activates the uncoupling on a trailing car which is not directly connected to the powered locomotive, then it is possible for the uncoupled car to drift and roll away if it is located on an inclined section of track. Further, the coupled cars which remain connected to the locomotive will go into an emergency braking in which the brakes become set. This is contrary to what should actually happen. In practice, the passenger car which remains coupled to the locomotive should be free to be pulled away while the uncoupled cars should have their brakes set.